2302D0833 Lumidor Calibration Gas Equivalent By GASCO 100 PPM Carbon Monoxide, 50% LEL Methane, 40 PPM Hydrogen Sulfide, 15% Oxygen, Balance Nitrogen, contained in a 34 Liter Disposable Aluminum Cylinder, For Use with Any and All Gas Detectors, Cylinder Connection C-10, Calibration Certificate NIST, Made in the USA